A Randomized, Double-Blind, Placebo-Controlled Trial of Moclobemide in Patients With Chronic Fatigue Syndrome

Background: Chronic fatigue syndrome ischaracterized by prolonged and disabling fatigue and a range ofneuropsychiatric symptoms including depressed and/or irritablemood. To date, no medical or psychotropic therapies have providedclear symptomatic benefit.

Method: Ninety patients with chronic fatiguesyndrome, diagnosed with our system that approximates CDCcriteria, participated in a randomized, placebo-controlled,double-blind trial of 450 to 600 mg/day of moclobemide, a novelreversible inhibitor of monoamine oxidase-A.

Results: Fifty-one percent (24/47) of patientsreceiving moclobemide improved compared with 33% (14/43) ofpatients receiving placebo (odds ratio = 2.16, 95% confidenceinterval [CI] = 0.9 to 5.1). Drug response was best characterizedsymptomatically by an increase in the subjective sense of vigorand energy rather than a reduction in depressed mood. The effectof moclobemide on subjective energy was detectable within thefirst 2 weeks of treatment and increased across the course of thestudy. The greatest reduction in clinician-rated disability wasin patients with concurrent immunologic dysfunction (meandifference in standardized units of improvement = 0.8, 95% CI =0.03 to 1.6).

Conclusion: Moclobemide produces someimprovement in key symptoms experienced by patients with chronicfatigue syndrome. This effect is not dependent on the presence ofconcurrent psychological distress and is likely to be shared withother monoamine oxidase inhibitors.